Knife-switch.



Patented May 29, I900.

No. 650,4I6. C. G. PERKINS.

KNIFE SWITCH.

licatiou filed Jan. 17, 1900 (No Model.) 2 Sheets-Sheet III T? I w a l I I Patented May 29, I900.

C. G. PERKINS.

KNIFE SWITCH. (App ica-tion filed Tani 17, 1900 (No lot! I) 2 Sheets-Sheet 2.

UNITED STATES PATENT OFFICE.

CHARLES G. PERKINS, OF HARTFORD, CONNECTICUT;

KNIFE-SWITCH.

SPECIFICATION forming part of Letters Patent No. 650,416, dated May 29, 1909.

Application filed January 17, 1900. Serial No. 1,765. (No model.)

To aZZ whom it may concern:

Be it known that I, CHARLES G. PERKINS, a citizen of the United States, residing at Hartford, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Knife-Switches, of which the following is a specification.

This invention relates to an inclosed fuse knife-switch.

The object of this invention is to provide a knife-switch with the movable conductors, which are adapted to be engaged with and disengaged from the stationary contacts for closing and opening the circuit, formed of metal that will fuse when an excess of electricity is in circuit and inclosed in insulation for protection and to render impossible a short circuit from one to the other and so attached that they may be quickly removed from and inserted into place.

In the forms of the invention illustrated by the accompanying drawings the parts which are pivoted to stationary contacts secured to the insulating-base and which are provided with a handle by means of which they may be moved for opening and closing the circuit are formed of blocks of insulating'material, with metallic strips at each end arranged to receive and detaohably hold the metallic caps on the ends of the tubular insulating-sheathing of the fusible conductors.

Figure 1 of the drawings shows a plan of a two-wire knife-switch that embodies the invention. Fig. 2 is a side view of that switch. Fig. 3 shows an end view of the same. Fig. 4 is an enlarged perspective view of one of the movable parts of the switch. Fig. 5 is a side elevation of the switch with the insulated fusible conductors held to the insulatingblocks in a modified manner. Fig. 6 is an end view of a three-Wire switch with the insulated fusible conductors fastened in the manner illustrated in Fig. 5. Fig. 7 is an end View of a two-wire switch with a double set of insulated fusible conductors held to each insulating-block, and Fig. 8 shows a side elevation of a reversible 01' double throw knife-switch provided with double sets of illsulated fusible conductors.

The base 1 is preferably formed of slate or porcelain, but of course may be made of any other suitable insulating material, and secured to the base the approved distances apart are the desired number of stationary contact-posts. In the forms illustrated each of these contact-posts consists of a pair of conducting-plates 2, that at their lower ends are fastened to a conducting-block 3, which has a perforation 4 and a binding-screw 5 for the insertion and securing of an end of the linewires of the circuit in which the switch is placed. v

The two-wire switch illustrated in Figs. 1, 2, and 3 has four stationary contact-posts, and pivoted to two of these, so as to swing into and out of engagement with the other two, are insulatingL-blocks 6. For making electrical connection with the plates of the stationary contacts each of these blocks, at both ends, is provided with a metallic strip 7, that has its ends shaped to form springfingers 8. The fusible conductors 9 are preferably inclosed in insulating tubular sheaths 10 and are connected with metallic caps 11 on the ends of the sheaths. These caps are adapted to be thrust into and be tightly clasped by the spring-fingers 8, that make electrical connection with the stationary contacts. The spring-fingers are shaped to permit the easy insertion of the caps connected with the insulated fusible conductors, and the insulating-blocks are preferably grooved to receive the conductor-sheaths and notched to allow the sheaths to be readily grasped for withdrawing the caps from the spring-fingers. The spring-fingers make good electrical connection with the fusible conductor-caps, and

an efiective contact between these parts is insured by the pressure of the plates of the stationary contacts between which the insulating-blocks, with the removable insulated fusible conductors, move. The insulating-blocks are joined by an insulating-bar 12, and attached to the bar is a handle 13, which is utilized for swinging the blocks on their pivots and opening and closing the circuit.

In Figs. 5 and 6 the sheath-caps 14, to which the fusible conductors are connected, are provided with flanges 15, and these flanges are held by screws 16 to metal strips 17, secured I00 to the ends of the insulating-blocks 18. In this instance the insulating-blocks are not grooved, and the insulating-sheathings 19, iiiclosing the fusible conductors, lie upon a flat surface.

In the form illustrated in Figs. 7 and 8 the insulating-blocks 20 are grooved upon both top and bottom faces, and the metallic strips 21 are arranged to provide spring-fingers 22 on both sides, so that the removable insulated conductors may be thrust into the clasp of the fingers on either or both sides of the blocks.

The invention is applicable to one, two, three, or more wire switches and also to double or reversible throw switches, as illustrated in the drawings. The stationary contacts may be formed in any desired shape, and the fusible conductors may be removably held in position by any suitable means, and of course the invention is equally applicable to knifeswitches which have the movable parts pivoted or hinged to posts that are not employed as conducting-contacts.

A switch formed according to this invention combines the advantages of an approved knife-switch and a safety-fuse block. The contacts are as effective as in any knifeswitch and the break is as sure. The insulated fusible conductors can be quickly placed in or removed from position, and there is no danger of short-circuiting the current by accidentally connecting the removable parts of the switch With a tool when they are being installed and the Wires connected, as in the ordinary knife-switch.

A switch embodying this invention is simple, effective, and safe.

I claim as my invention- 1. In a knife-switch in combination, a base,

' stationary contacts secured to the base, insusulating-sheathin gs, substantially as specified.

2. In a knife-switch, in con1bination,a base, stationary contacts secured to the base, insulating-blocks, metallic strips connected with the ends of the insulatingblocks and shaped to form spring-fingers, the metallic strips at one end of the blocks being movably connected with some of the stationary contacts and the metallic strips at the other end of the blocks being adapted to be moved into and out of engagement with other of the station ary contacts and fusible conductors removably held by the spring-fingers, substantially as specified.

3. In a knifeswitch in combination, a base, stationary contacts secured to the base, insulating-blocks, metallic strips connected with the ends of the insulating-blocks and shaped to form spring-fingers, the metallic strips at one end of the blocks being movably connected with some of the stationary contacts and the metallic strips at the other end of the blocks being adapted to be moved into and out of engagement with other of the stationary contacts, and insulated conductors removably held by the spring-lingers, substantially as specified.

4. In a knife-switch in combination, a base, stationary contacts secured to the base, insulating-blocks, metallic strips connected with the ends of the insulating-blocks and shaped to form spring-fingers, and insulated fusible conductors removably held by the spring-fingers, substantially as specified.

5. In a knife-switch in combination, a base, stationary contacts secured to the base, insulating-blocks, metallic strips connected with the ends of the insulating-blocks with the ends of the strips forming spring-fingers on both sides of the blocks, the metallic strips at one end .of the blocks being movably connected with some of the stationary contacts and the metallic strips at the other end of the blocks being adapted to move into and out of engagement with other of the stationary contacts, and fusible conductors reinovably held by the spring-fingers on both sides of the blocks, substantially as speei lied.

CHARLES G. PERKINS.

W'itnesses:

HARRY R. WILLIAMs, O. E. BUCKLANDM 

